Blue Ox Broken Tow Bar bolt questions

[4rickyg]

On my way home from a 2000 mile trip. Stop at the rest stop At the Florida line. Did my walk around and found the head of this bolt sheared off. Was only a 100 miles from home. Did not want to take any chances so I unhooked the toad and had the DW drive it home.

  Not sure how these things are constructed. Thought I would ask here for some advice before I before I start to take it apart. As always thanks for your help.

[Fasthobie16]

The bolt pictured appears to be a grade 5 bolt ( three line marks). If it was my setup and a grade 5 bolt failed, I would replace it with a much harder grade 8 bolt (6 marks on head). 
Along with a grade 8 lock nut. On top of that, if you have some room to drill a small hole just beyond the lock nut for a cotter pin for additional security. 
Also I’d check the other bolts I see in pics for wear an replace it needed. It looks like the moving joints where the bolts are haven’t been lubed in some time. I see rust. ( Could be contributing to failure.) Squirt  some oil on them occasionally.  Moving parts née lubrication. 
Off topic, but maybe not.  How long has it been since you’ve taken your tow bar boots loose and cleaned and greased the cylinder rods? YouTube has videos on that procedure.  A well maintained and lubed tow bar aids in the hookup, locking, and unlocking of it. 
 

Edited August 16, 2022 by Fasthobie16
Added info.

[4rickyg]

Thank you 

[Fasthobie16]

Hey 4rickyg, 

Added a little more information that may interest you on my post. 

[Ray Davis]

In pict #1 & 2  I see the locking plate sticking up with the swivel on one side and a hole on the other.

In pict #3   I can see the other side of the square bar and a bolt head.  Is that the bolt in question?

[Dr4Film]

I am trying to figure out what he is describing also.

[LakeBob]

I’m trying to figure out the problem as well

[Fasthobie16]

I don’t see the sheared bolt either in the pics. Pictures could be from before problem or after. Either way OP said he had a failed bolt. He did the correct thing and unhooked the toad and had the DW drive it home instead of trying to  jury-rig it there. 

[Dr4Film]

2 minutes ago, Fasthobie16 said:

He did the correct thing and unhooked the toad and had the DW drive it home instead of trying to  jury-rig it there. 

I agree. No sense in taking any chances for 100 miles. The risk is too great.

[4rickyg]

In picture 1 and 2 right next to the label that says 10,000 pounds you'll see a round hole. That is Where's something sheered off. Picture 3 is the side with the bolt head.

[Dr4Film]

Thanks, that explains it.

I am thinking that I read somewhere on this site about a Blue Ox Tow Bar failure where Blue Ox had issued an upgrade but you had to know about it or if you had sent the bar in for service they would have performed the upgrade automatically.

Not sure if it is even the same model.

You could try a search on the site to find it.

I remember now that it was the Avail Model Blue Ox Tow Bar.

Edited August 16, 2022 by Dr4Film
Tow Bar Model

[Fasthobie16]

Hole was a little bit hard to make out. Ok. See it now fix it.

Blue Ox may or may not warranty your unit depending on age. 

Edited August 16, 2022 by Fasthobie16
Added info

[Old Dog]

Be careful substituting grade 5 & 8 bolts unless you understand what you're doing. This can lead to real problems. Grade 5 bolts are maluable where as grade 8 are more brittle, there are other qualities as well that factor into the selection. They are, or should be selected for specific applications. I would guess looking at the photos that oxidation, i.e. rust played a factor but given a potential recall it may simply be selecting the cheaper rather appropriate fastener.

There's plenty of info on fasteren available, enough to give you a headache. I would definitely call the company, given the liability issues they my fix the unit and perform a rebuild of the entire thing. Hope this helps

[cbr046]

Would it be prudent to re-drill the hole for a larger diameter bolt (without knowing what the inside sleeve looks like)?

Like Old Dog said, could lead to bigger problems . . . . . maybe contact Blue Ox for real engineering advise. 

- bob

[4rickyg]

There is a blue ox dealer right down the road from me. The hitching post, Ocala Florida. I will run it by them  when I have time to see what they say.

[Dr4Film]

29 minutes ago, 4rickyg said:

There is a blue ox dealer right down the road from me. The hitching post, Ocala Florida. I will run it by them when I have time to see what they say.

The Hitching Post of Ocala is also an excellent Aqua-Hot Certified Service Center. Butch is the only service tech in the shop that works on Aqua-Hot units. I consider him one of the best in Florida that you can find. It took me some time to find them after having "certified" mobile techs waste my time and money.

I drive 80 miles each way from Flagler Beach to Ocala and back to have my Aqua-Hot serviced by them.

[Tom Cherry]

I was the engineering manager for a fastener company and also 10 years of front line experience as the Manufacturing Services Director for two maintenance and tool room shops.  I have also designed some heavy duty machines and structures….and I always follow the best practices specified by the Fastener Bible or the IFI Handbook.

First…drilling a grade 8 bolt usually takes a drill press and a special bit and slow speed as lots of lubricant.  Not something I’d do at home….but it could be done.  However I would NOT re-engineer a tow bar mount or fasteners without a lot of input from the vendor.  

Second… I would contact Blue Ox and get tech support and their guidance.  There were some defective Tow Bars in the early 2000’s and Blue Ox swapped them out.  They had a crew at Daytona 500 and walked around and inspected them and had a van full of new bars…. I know because two were swapped….and one was the GM of a HR dealer….who sold them.

Third….the tow bar looks like there is a loose bolt with the large “fender” washer.  This is what I would do….

Download the prints on the tow bar and the mounts.  What confuses me is the second receiver hitch in the first picture above…. The length of the draw bar on the hitch is something that I have not seen before.  It is long and there is (not can be) a lot of play.  There are some “Hitch” tightners sold on Amazon and Roadmaster makes them also.  A “U” clamp that secures it and eliminates play and such.  It really works and we have some Mechanical Engineers here that have done some things to reduce the play and the “tail wagging the dog”.  I use one on my Tow bar and also when I hook up my utility trailer to the Yukon.

FINAL comment.   When you download the prints, there should be a bill of material or a pictorial and the size and grade will be called out…at least for Roadmaster.

There was a lot of discussions on the old site.  I also spent time on the phone with tech support and also the head of the Roadmaster install shop in Oregon.  I would get a bottle of Loctite RED and remove each fastener and use Loctite Red. Again, my worry is the large bolt in the draw bar going back.  Get the torque specs from Blue Ox or look them up.  There are many engineering tables online.  Some say dry or no plating.  Some say zinc which is actually the finish on most bolts….it is NOT chrome, but a zinc electroplated finish with a clear chrome “film” to resist corrosion, some say “wet”…that means if you use a lubricant to prevent galling or seizing up.  Is that CLEAR?  LOL.  I always use the DRY value and do USE Loctite….and have a good torque wrench. The same advice goes for the mounts on the vehicle.

Yes, I, too, am a bit confused as to which bolt and where.  
 

BTW…you do know that about every 5 - 7 years Blue Ox and Roadmaster recommend having the tow bar inspected but an AUTHORIZED dealer and having their “Rebuild Kit” installed.  The folks at Roadmaster sent me a kit, as a courtesy and after 50K of use, I started to install it but Tom Johnson in Marion had a “hitch shop” with 3 full time employees and the foreman did it for $60…

I traded up and got a heavier vehicle and sold the one that was too light for my Yukon.  The rebuild actually made the Hummer H3 less noticeable when towing.

you MIGHT ought to look into that.

 

[jacwjames]

I an going to check my tow bar, I think I have the same one, not sure if mine has the bolt.

But out of curiosity I downloaded the installation instructions that also have the parts page.  This document does not show that bolt.  It does show 3 lengths of the  connector assemblies.  The standard length is 12.69" but there is a longer one at 16.69". 

I need to take mine apart and go through it. 

[Ivan K]

Mine does not even have a hole in that area.

[Dr4Film]

I just performed a Google Image Search for Blue Ox Aventa II Tow Bars and there were a number of images that had the bolt in that location and a number of images that did not.

It appears that there may have been TWO versions of the Aventa II Tow Bar. Why some have it and some not, only Blue Ox can answer that question.

I use the Blue Ox Aventa LX Tow Bar which is also rated at 10,000 lbs. Never had any problems and always service it once a year usually just before our traveling season which starts in the spring.

[jacwjames]

1 hour ago, Dr4Film said:

I just performed a Google Image Search for Blue Ox Aventa II Tow Bars and there were a number of images that had the bolt in that location and a number of images that did not.

It appears that there may have been TWO versions of the Aventa II Tow Bar. Why some have it and some not, only Blue Ox can answer that question.

I use the Blue Ox Aventa LX Tow Bar which is also rated at 10,000 lbs. Never had any problems and always service it once a year usually just before our traveling season which starts in the spring.

Richard, have you had to replace any major parts?

[Dr4Film]

38 minutes ago, jacwjames said:

Richard, have you had to replace any major parts?

No major parts whatsoever. Just clean and lube all of the important areas and check the boots for cracks.

[jacwjames]

I actually own two of the BX7335 Avante II Blue Ox tow bars.   I found a used one for a really good price so I bought it. 

I checked them today and one has the bolt and the other does not, go figure.  Without taking them apart no idea what the purpose of the bolt is but looking at the parts diagram I wonder if it has some sort of function to lock the nut from coming off.  I guess I could try and remove the bolt and see if I can tell what function is serves.

[hex_nut]

Attached is a picture of the yoke attachment for that version of tow bar.  The two small bolts that go in from the sides are locking bolts that secure the nut of the main bolt that holds the yoke into the square channel. The locking mechanism was redesigned by Blueox at some time during the manufacturing process.  That is why you see some of them with the 2 small bolts and some of them without.  This is an old unit and probably past its usable life.  Before I would spend much time and money repairing this, I would instead be looking to replace it with a new one.

Richard

[jacwjames]

3 minutes ago, hex_nut said:

Attached is a picture of the yoke attachment for that version of tow bar.  The two small bolts that go in from the sides are locking bolts that secure the nut of the main bolt that holds the yoke into the square channel. The locking mechanism was redesigned by Blueox at some time during the manufacturing process.  That is why you see some of them with the 2 small bolts and some of them without.  This is an old unit and probably past its usable life.  Before I would spend much time and money repairing this, I would instead be looking to replace it with a new one.

Richard

Thanks, explains a lot.   Wonder if the earlier model had problems with the nuts coming loose, hence the design change.

Time for me to take both mine apart and inspect, clean, lubricate.